Neil Mula


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  • 1-wire or Single-Line Overvoltage Protection

  • Created: Mar 22, 2016

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The single-line or 1-wire communication protocol is quite sensitive communication that it cannot allow standard means of fault protection like large series resistors or large line capacitances. In this design, MAX9940 is used as an overvoltage protector in which it has extended ESD Protection of ±4kV IEC 61000-4 Contact on EXT pin. The operating voltage range is +2.2V to +5.5V and the quiescent supply current is at 13μA. It has fast fault reaction time that is 60nanoseconds.

The design is comprised of MAX9940 single-line overvoltage protector in which it protects the microcontroller from high-voltage faults and ESD strikes on EXT pin. The VDDs of MAX9940 is powered directly, and consumes quiescent current on a continuous basis. The internal FET between INT and EXT is kept on as long as the voltage on EXT is below VCC. As a result, in the event of a short to GND fault on EXT, current is drawn through R1. The DS18S20 digital thermometer IC serves as a temperature sensor with 1-wire protocol. It can be modified to add another 1-wire device in the design.

This design with single-line overvoltage protection is applicable to battery operated devices like notebook computers and portable device. It is also applicable to nonbattery-operated applications like manufacturing industry equipments.



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